1. Field of the Invention
This invention relates generally to fatty acids and, more particularly, to a new process for the production of conjugated linoleic acid by enzymatic hydrolysis of its esters.
2. Prior Art
Linoleic acids with conjugated double bonds, which are commercially available as “CLA” (conjugated linoleic acids), are physiologically active and are used as food additives. Conjugated linoleic acid is normally produced from triglycerides which have a high percentage content of—normally unconjugated—linoleic acid, such as thistle or sunflower oil for example. The triglycerides are isomerized in the presence of basic catalysts or enzymes and then saponified. A disadvantage in this regard is that, on the one hand, the saponification step yields many unwanted waste materials and, on the other hand, large quantities of alkalis are required, which can quickly result in corrosion in the reactors used. To avoid this, linoleic acid alkyl esters have more recently been used as preferred starting materials and, in a first step, are isomerized to the CLA esters and then saponified. However, even this process is not entirely convincing because it is also attended by disadvantages, such as for example poor yields, drastic reaction conditions, unwanted secondary products and long reaction times.
Accordingly, the problem addressed by the present invention was to provide a process for the production of conjugated linoleic acid which would reliably avoid the above-mentioned disadvantages of the prior art.